The invention is generally directed to a character pattern generator for European including English-language alphabet character sets adapted for use in a dot matrix printer and in particular in a dot matrix type printer capable of fixed pitch and proportional pitch printing. Dot matrix type printers, such as wire type dot printers, ink jet type printers and heat transfer type printers, form characters and/or figures by printing a series of dots while moving the print head transversely across the paper. The head includes a plurality of dot generating mechanisms arranged to extend substantially parallel to the paper feeding direction. Character codes transmitted from another device such as a computer, are converted into dot patterns prior to driving the print head to produce the desired dots.
Printers adapted to print European language alphabet characters are frequently configured to print both fixed pitch and proportional pitch characters, often in the same document. Fixed pitch printing is accomplished by specifying a fixed character matrix, for example a 7.times.9 character matrix, with each character being assigned an entire matrix. In proportional pitch printing, in contrast, narrow characters are assigned smaller matrices while wider letters are assigned wider character matrices to provide a more natural and "printed" appearance to the finished results.
The need for a single printer to be able to print with both fixed pitch and proportional pitch spacing has required two complete sets of dot pattern data to be stored in the character generator. The first dot pattern data set is for fixed pitch printing and the second is for proportional pitch printing. As a result, both sets must be stored in a memory device which is thus required to have a large capacity which results in increased cost for the character pattern generator and the printer as well.
There is, therefore, need for a character pattern generator for a dot matrix printer which reduces the number of different character dot pattern data required for fixed pitch and proportional pitch printing of European including English language alphabet characters.